A polyimide film has been extensively used in the fields of electric/electronic devices, semiconductors and so on, because of its excellent heat resistance, chemical resistance, mechanical strength, electric properties, dimensional stability and so on. For example, for a flexible printed circuit board (FPC), there has been used a copper-clad laminated substrate where a copper foil is laminated on one or both sides of a polyimide film.
A polyimide-metal laminate is most commonly produced by laminating a polyimide film with a metal layer such as a metal foil via an adhesive layer, but its heat-resistance or adhesiveness is not sufficient for some applications. For example, Patent Document No. 1 has described a process laminating polyimide having a superficial thermally compression-bondable polyimide layer with a metal foil such as a copper foil by thermal compression-bonding. A polyimide-metal laminate thus produced is excellent in heat resistance and adhesiveness. However, a material which can be used as a thermally compression-bondable polyimide is limited.
Meanwhile, Patent Documents 2 and 5 have described a polyimide made from a triazine-based diamine and examples where a polyimide solution was applied to a metal foil to produce a laminate of the metal foil with the polyimide film.
Furthermore, as examples of the use of a triazine-based diamine, Patent Document 3 has disclosed a terminal-modified imide oligomer based on a triazine-based diamine and Patent Document 4 has disclosed a polymer electrolyte based on a triazine-based diamine.